The Ivory Coast international, who notched 15 goals and 10 assists to help the French side to their first league title in 57 years last term, arrives at the Emirates for a fee believed to be €12 million, although the length of his contract has not been revealed.
Wenger revealed the news about Gervinho as his side arrived in Malaysia, without their newly acquired forward, ahead of their pre-season tour of the Far East.
"Gervinho has come back from holiday and signed," said Wenger.
"He had a medical on Thursday and we sent him back home to sort things out for two days. He has a family with children.
"He came back yesterday and starts his fitness programme in London today. He is officially an Arsenal player now. I decided not to take him because he had had no training sessions."
The Gunners reportedly agreed personal terms with the 24-year-old last month, but have spent the intervening period in talks with Lille over an agreed price.
Gervinho becomes the second summer arrival at the Emirates Stadium after the signing of full-back Carl Jenkinson from Charlton Athletic, as Wenger looks to revamp his squad in a bid to end the club's six-year trophy drought next term.
The news could well constitute the final nail in the coffin of Nicklas Bendtner's Arsenal career, with the striker currently the subject of interest from Borussia Dortmund and Sporting Lisbon as well as several English clubs.
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